Automobile light



April 14, 1925.

W. H. WOOD AUTOMOBILE LIGHT Filed Dec. 17, 1924 2 Sheets-Sheet lArrow/5V5 April 14, 1925.

r r 1,533,360 w. H. wboo AUTOMOBILE I I GHT Filed Dec. 17. 1924 2heets-shut 2 Patented Apr. 14, 1925.

, UNITED STATES WILLIAM H. WOOD, OF SOUTH EUCLID, OHIO.

AUTOMOBILE LIGHT.

Application filed December 17, 1924. Serial No. 756,495.

To all whom it may concern:

Be it known that I, \VILLIAM H. 7001), a citizen of the United States ofAmerica, and a resident of South Euclid, in the county of Cuyahoga andState of Ohio, have invented certain new and useful Improvements inAutomobile Lights, of which the following is a full,"clear, and exactdescription.

This invention relates to automobile lights and has for its main objectthe provision of a new and improved lamp bulb having its light producingelements so shaped and arranged as, when used with customary types ofreflectors, to produce a beam of such shape as shallbe most satisfactoryto the driver of the vehicle and at the same time least objectionable totravelers moving in the opposite direction; the provision of a lamp bulbwhich, when used with a reflector of the conic section type, shallproduce a legally acceptable and practically desirable light without theadded employment of lenses, dimmers, special reflectors, etc.-; theprovision of a lamp bulb which, when used with reflectors of thecustomary, type, shall produce a diffused illumination of its chosenfield and at the same time shall illuminate different portions thereofwith varying intensities; the provision of a headlight bulb having ahigher factor of safety than previous devices used for this purpose;while further objects and advantages of the invention will becomeapparent as the description proceeds.

In the accompanying drawings I have shown several physical forms inwhich my inventive idea is embodied together with the result obtained byusing a preferred form of my improved lamp bulb in connection withparaboloid reflectors. Fig. 1 is a plan view of a bulb showing one formof filamentary arrangement; Flg. 2 1s a side elevation showing apreferred form of leading-in wires; Figs- 3 and 4 show a side elevationand plan of a bulb having multiple leadingin-wires and independentlyoperable filaments also embodying my improvements; Figs. 5 to 9inclusiveillustrate alternative filamentary arrangements; Fig. 10 is a centralvertical sectional view through a paraboloid reflector showing therein alamp of the type illustrated in Figsfl, and 2; Fig. 11 is a verticalsectional view like Fig. 10 but taken sufficiently to one. side of thecenter to intersect the ends of the filaments; and Fig. 12 is ananalysis of the light pattern as cast upon a vertical screen by a lampbulb of the construction herein described in cooperation with a commonparaboloid reflector.

My improved lamp comprises the usual glass globe or bulb 1 and press 2,the latter having the usual leading-in wires sealed therein, togetherwith a suitable metal base 3, usually of cylindrical shape, having oneor more insulated contact points 4, or 5, 5, carried thereby. The numberof leading-in wires varies with the use of the lamp and the number ofuses for which it is intended, and the number, shape and arrangement offilaments also varies. In Fig. 1 I have shown two leading-in wires 6, 6,having secured thereto at points spaced longitudinally along the bulbaxis a-a three straight crosswise filaments, 7, 7, constituting a planelattice. Usually these filaments are of fine wire coiled to helicalform, and the term straight as I have used it relates to the axis of thehelix. Because of their electrical connection these filaments areilluminated simultaneously. Usually they are of equal candle power, sayeach of 6, 10, 12, 15, or 21 candle power, although they can be made ofunequal candle power if desired. For example in sections where legalrequirements are severely exercised upon drivers whose lamps haveaccidentally burned out it is possible to incorporate one filament oflow efficiency but proof against burning out. They are spacedsufliciently far apart to come into focus at different times, wherebythe light cast by one filament may dissolve any shadows pro- ,duced bythe others, either from its location or by reason of inequalities in thereflector (or other light controlling device). The considerations whichdetermine the length and spacing of these filaments will be set forthhereafter. Here it is noted that I .do not limit myself to using threefilaments since any number greater than one can be used" as shown inFigs. 1 to 9; and that they need not be straight but can be V-shaped asin Figs. 6 and 7, or curvilinear as in Fig. 8; and that they need not beparallel but can intersect as in Fig. 9 or be otherwise disposed. Alsoas to their electrical connection, two leading-in wires can be attached,one tothe base 3 and one to the center contact 4: as shown in Fig. 1; oreach to an independent insulated contact 5, 5 as shown in Fig. 5.

An important feature of the present invention is the location ofsuccessive filaments not only at spaced points along the lamp axis butalso at progressively varying distances away from that axis therebyprosubstantially a plane, the filaments consti-- tuting in effect a kindof lattice although minor variations from a strict plane are notimportant. In order to produce this effect most easily the tips of theleading-in wires are preferably deflected as; shown in Fig. 2; and theoperation of the lamp is most satisfactory when the foremost filamentsubstantially touches the lamp axis, .the filaments to the rear thereofbeing offset fromtbat axis as shown in Fig. 2.

The result produced when such a lamp bulb is employed in a paraboloidhead light reflector is shown in Figs. 10 to 12. It is essential thatthe filaments be substantially horizontal and that the filament latticerise from front to rear, the foremost filament being locatedsubstantially on the focal point. The direction of the reflected beamsarising from-the ,middle points of the various filaments is shown inFig. 10 from which it will be seen that a part is thrown above thereflector axis; but this is true only of the light rays arising at themiddle points of the filaments since owing to the elevation of thefilaments above the horizontal the light arising from the end portionsthereof is deflected downwardly from all parts of the reflector asattempted to be shown in Fig. 11. As a result the light pattern as caston a vertical screen is substantially shown in Fig. 12, wherein region Xis illuminated by the first or focussed filament, region Y by the nextfilament and region Z by the third filament; this can be carried furtherif desired but three is suflicient toshow the operation. The uppercorners of the pattern (the D points) which ordinarily cause theblinding and dazzling rays are eliminated and in their stead a curb andgutter light is produced known legally as the Q, points. The centralupper portion above the axis a-a, known as the C point is feebly lightedby the rays arising from the middle points of the rear-most filaments asheretofore explained, although this region is neither wide nor is itintensely illuminated and the most intense part of the beam comes at B,just below the extended axis a of the lamp,'this being the exactdistribution required by the regulations of even the most exactincommunities.

My improved filamentary arrangement can be combined with anindependently usable filament of the same or different candle power ifdesired for city driving or parking purposes. In this case threeleading-in wires are employed as shown in Figs. 3 and 4, two of the sameas 6 and 8 supportiueeasee ing the high power filaments 7 7- and thethird 9 supporting one end of the independent filament 10, whose otherend is fastened to one of the first leading-in wires as 6. This commonterminal is preferably grounded to the base, and the others areconnected to the insulated contacts 5, 5. This independent filament canbe used either with the straight .or the deflected leading-in wires,but-is preferably kept as near the focal point as practical. It may beeither of the same or of different candle power as the main filaments,inequality of illumination being obtained in large degree bythemultiplication.

Another feature of my improved lamp bulb is that it has to be moved asubstantial distance along the reflector axis before the character ofthe light beam is appreciably changed, thus, in effect, approaching thedesirable condition of universal focus.

In certain of my claims I have employed the expressions planejsubstantially a plane, and similar words, but it is to be understoodthat I do not intend thereby. to confine myself to a true geometricplane,

wholly without thickness and entirely with-- out irregularities, butdesire to include such human variation from flatness and such approximations to smoothness as still produce the results hereindescribed.

I do not restrict myself to the use of this lamp with any specific formof reflector or lens, although certain features of my improved lampexhibit their complete advantage only when used with reflectors of theconic section type such as the common paraboloid variety and one of itsmain advantages is that it does not require the employment of anyspecial lens or peculiar warping of the reflector to eliminate glare. Itwill be understood, however, that lenses and warped reflectors may beused in addition thereto and that I do not limit myself to dcing-inwires being so deflected relative to the lamp axis that the plane ofsaid lattice is oblique thereto.

2. A lamp-bulb for the purpose described comprising a globe, a basecoaxial with said globe, and a lattice of simultaneously usable luminousfilaments located inside said globe and defining a single plane whichintersects at an oblique angle thecommon axis of said base and globe.

3. An incandescent lamp bulb comprising wires and'arranged cross-wise ofthe lamp axis, said filaments being confined substantially within asingle plane which intersects the bulb axis obliquely.

4. An incandescent lamp a press, non-luminous leading-in wire prejectingtherefrom, a plurality of luminous filaments connected across the freeends of said leading-in wires in multiple circuit, said filamentsdefining substantially a plane lattice and the tips of said leading-inwires being bent so as to cause the plane of said lattice to intersectthe bulb-axis obliquely.

5. An incandescent lamp bulb comprising a globe and a base, a pair ofnon-luminous, leading-in wires projecting into said globe from said baseand having their free ends substantially parallel to each other andspaced apart laterally, said free ends being bent so as to defineoblique angles with the common axis of said base and globe, and aplurality of luminous filaments connected across the free ends of saidleading-in wires in multiple circuit, said filaments togetherconstituting a plane lattice which is located wholly at one side of thecommon axis of said base and globe.

6. An incandescent lamp bulb comprising a globe and a base concentric toa common axis, a pair of non-luminous, leading-in wires projecting intosaid globe from said base and confined to adjacent quadrants about saidaxis, the .tips of said leading-in wires being parallel to and spacedfrom the meeting plane between said quadrants and also oblique to andterminating substantially at the bounding planes of said quadrants, anda plurality of luminous filaments con nected across thetips of saidleading-in wires in multiple circuit.

7. An incandescent lamp bulb comprising a globe and a base concentric toa common axis, a pair of non-luminous, leading-in wires projecting intosaid globe from said base and confined to adjacent quadrants about saidaxis, the tips of said leading-in wires being parallel to and spacedfrom the meetin plane between said quadrants and also 0 lique to andterminating substantially at the bounding planes of said quadrants, anda plurality of V-shaped filaments connected parallel to each otheracross the tips of said leading-in wires, each filament consisting of afine wire wound in a small helix and the ciding with the inclmed planedefined by the tips of said leading-in wires.

8. An incandescent lamp bulb comprising bulb comprising lam lanes ofthe. Vs coin-' a globe and a base, a pair of non-luminous, leading-inWires projecting into said globe from said base and having their freeends substantially parallel to each other and spaced apart laterally,said free ends being bent so as to define oblique angles with the commonaxis of said base and globe, but

without crossing that axis, and a plurality of V-shaped filamentsconnected arallel to each other across the free ends 0 said leadinginwires, each filament consisting of a fine wire'wound, in a small helixand the planes of the VS coinciding with the inclined plane defined bythe free ends of the leading-in wires, the VS nested one within theother but without touching, and the apex of the foremost V terminatingsubstantially at the common axis of the base and globe.

9. An incandescent electric lamp bulb having therein a plurality ofsimultaneously illuminated filaments arranged transversely of the lampaxis at unequal distances from the base certain of said filaments beingdisplaced from said axis in a direction perpendicular to'said filamentso as to define substantially a single plane which meets said axisobliquely.

10. An incandescent electric lamp bulb having therein a pair oflongitudinal leading-in wires and a plurality of filaments connectingsaid wires in multiple circuit, said filaments being arranged crosswiseof the bulb axis and at different distances therealong and certain ofthe same being displaced to one side of said axis and other of the sameintersecting said axis, said filaments defining and confined within asingle plane which meets said axis at an oblique angle.

11. An incandescent electric lamp bulb having therein a plurality ofsimultaneously illuminated filaments arranged transversely of the lampaxis and at unequal distances from said axis and also from the lampbase, said filaments defining a single inclined plane.

12. An incandescent electric lamp bulb having therein a plurality ofsimultaneously illuminated filaments defining and confined .within aplane which intersects the lamp axis obliquely.

13. An incandescent electric lamp bulb having therein a plurality of"simultaneously illuminated filaments defining and confined within aplane which intersects the axis obliquely said filaments being con nedsubstantially to a region at one side of the lamp axis.

In testimony whereof, I hereunto afiix my signature.

WILLIAM H. WOOD.

